Glycoprotein D (g')) is an essential envelope protein from the herpes simplex virus (HSV). The two strains of HSV, HSV-1 and HSV-2, both contain g'), and g')-1 and g')-2 are 80% homologous in sequence. Truncated versions of the two proteins have been cloned in a baculovirus expression system. The proteins have all the amino acids necessary for flinction including in vitro assays, have the proper conformation, and are soluble since they are truncated at amino acid 306 prior to the hydrophobic transmembrane region. They are called g')-1(306t) and g')-2(306t). Two additional mutants of g')-1(306t) have been cloned and expressed. Whereas the wild-type has three N-linked carbohydrates, g')- 1 (TAAt) has only one and g')- 1 (QAAt) has none. Both proteins have the proper conformation and flinction in in vitro assays. The protein g')-1(306t) appears dimeric by gel filtration data. Mass analysis in the STEM agrees with this and additional measurements on all four of these proteins indicate they are all dimers. The HSV glycoproteins H and L are found in the virus envelope as a hetero-oligomer. The purified gH(gL complex is being analyzed in the STEM to determine its molecular weight and to see if any structural details can be observed. GRANT NUMBER